Currently, with regard to DRLs, a standard for compliance has been set in Europe, and the USA, etc. It has been required that, in DRLs, the divergence of light includes a broad distribution in the horizontal direction with respect to the vertical direction.
As one conventional daytime running light (DRL), there is a DRL that emits light, which has been emitted from a light source, directly to the front direct ion using a lens or reflector. For example, there is a DRL that reduces high beams from the head light to change luminescence amounts of LED arrays, or the number of LED arrays emitting light so as to realize light distribution suitable for daytime running (for example, see Patent Literature 1).
FIG. 19 is a view that shows a conventional daytime running light described in Patent Literature 1. In FIG. 19, the daytime running light is a type in which the light is utilized also as a head light, and includes an LED array 11 having multiple LEDs and a lens 12. The light emitted from the LED array 11 is collimated by the lens 12. The light from LEDs close to the optical axis of the lens 12 is to be the light in the optical axis direction, i.e., in the front direction, and the light is emitted from the lens 12. On the other hand, the light from LEDS remote from the optical axis of the lens 12 is to be the light in the horizontal direction, and the light is emitted from the lens 12. Thus, in the daytime running light shown in FIG. 19, the luminescence amount of each LED of the LED array 11 is adjusted so as to realize light distribution suitable for daytime running.
Furthermore, as another example of a daytime running light, there is a daytime running light that uses a light guide plate to form a line-like light source (for example, see Patent Literature 2).
FIG. 20 is a view that shows a conventional daytime running light described in Patent Literature 2. In FIG. 20, the daytime running light includes a high-output LED 13, a light guide plate 14, and a prism 15 formed on the light guide plate 14. In addition, light 16 is also shown in FIG. 20. The light emitted from the high-out put LED 13 enters the light guide plate 14, and propagates through the light guide plate 14 while being totally reflected therein. When the light that has propagated through the light guide plate 14 enters the prism 15, a path of a part of the light is bent by the prism 15, and the part of the light deviates from conditions for the total reflection in the propagation thorough the light guide plate 14, and is emitted to the outside of the light guide plate 14.